Measurement of the degree of water acidity. It is determined by the amount
of acids and bases in the water. If the amounts are equal it is called neutral
with a number rating of 7.0. If more acids it is called acidic with number
rating of less than 7.0, if more base it is called alkaline with a number
rating of more than 7.0.

A process of filtering tap water for use in the
aquarium. Water passes through a membrane which filters out
all elements leaving the water very pure. Trace elements
you want will have to be adjusted as well as the pH

A type of filter placed under the substrate that
utilizes an air pump or power head to pull water through
the gravel and thus oxygenates the bacteria to help in the
nitrogen cycle. Not recommended for live plant tanks.

Name given to water with a slight yellow tinge. Can be
caused by too much organic material in the water or to show
that a water change is needed. Eliminated through carbon
filtration and better water management.